DEVICE AT RAILWAY WHEELS AND METHOD FOR OBTAINING SAID DEVICE

Abstract: The present invention relates to a device for improving the adhesitivity of surface refined parts (6) to the body (7) of railway wheels (1), which surface refined parts (6) have been produced by treating the railway wheel (1) with high energy generated preferably by laser radiation (8). In order to prevent or at least obstruct the risk for loosening of the surface refined parts (6) from the body (7) of the railway wheel (1), the maximum thickness (B) of the surface refined parts (6) is selected so that the Hertzian pressure which affects the railway wheel (1) when said wheel is loaded with the maximum permitted pressure thereon is substantially carried by the body (7) of the railway wheel (1) beneath the surface refined parts (6).

Description: Device at railway wheels and method for obtaining said device. The present invention relates to a device for impro¬ ving the adhesitivity of surface refined parts to the body of railway wheels, which surface refined parts have been produced by treating the railway wheel with high energy generated perferably by laser radiation. The present invention also relates to a simple method for obtaining said device. From DE, Cl, 35 09 582 it is known a railway wheel which has been surface refined or improved by means of laser radiation. However, the thickness of the surface re¬ fined parts is not maximized and said parts have therefore a substantial thickness. This results in that there is a great risk that said parts loosen, i.e. that so called flaking out occurs. The object of the present invention is to avoid this drawback, which according to the invention is arrived at by providing the abovementioned device with the characte¬ rizing features of claim 1. A method for obtaining said device comprises accor- ding to the invention the characterizing features of sub¬ sequent claim 3. Since the device having said characterizing features ensures that the Hertzian pressure is substantially carried by the body of the railway wheel, loosening of the surface refined parts from the body is prevented or obstructed. The invention will be further described below with reference to the accompanying drawings, wherein fig. 1 schematically illustrates a railway wheel on a rail; fig. 2 schematically illustrates a surface treatment of the railway wheel carried out in accordance with the method of the invention, whereby said surface treatment is a surface application; fig. 3 schematically illustrates a substantial magni- fication of a section of an area of the railway wheel at which surface application or surface coating according to fig. 2 has occured; fig. 4 schematically illustrates a surface treatment of the railway wheel according to the present method, where¬ by said surface treatment is a surface impregnation; fig. 5 illustrates a substantially magnified section of an area of the railway wheel at which surface impregna¬ tion according to fig. 4 has occured; fig. 6 is an enlarged section of a part of the rail¬ way wheel which in accordance with the method of the in¬ vention has been surface treated by surface application, whereby surface treating strings located beside each other have been integrated with each other; fig. 7 illustrates a section of a part of the rail¬ way wheel which in accordance with the method of the in¬ vention has been surface treated by surface impregnation, whereby surface treating strings located beside each other are integrated with each other; fig. 8 illustrates a section of a part of the railway wheel with a finished surface treatment provided in accor¬ dance with the present method; and figs. 9-14 schematically illustrates parts of railway wheels on which surface treating strings are applied in accordance with the method of the invention in various patterns. The railway wheel 1 illustrated in the drawings has a wheel tread 2 through which it is adapted to roll or run on a rail 3. The railway wheel 1 further includes a rail flange 4 which in a manner known per se ensures that the wheel can not move laterally relative to the rail 3 such that it ends up beside said rail. The railway wheel 1 also includes an arcuate transition portion 5 between the wheel tread 2 and rail flange 4. Central parts 5a of this transi- tion part 5 have a smaller radius than the radii of outer parts 5b, 5c on opposite sides of said central parts 5a. When the railway wheel 1 rolls on the rail 3 during move- ment thereof on straight distances, in curves, on climbs, over switches and so on, it is the transition portion 5, the part 2a of the wheel tread 2 closest to said transi¬ tion portion 5 and the part 4a of the rail flange 4 closest to said transition portion 5, i.e. those parts 2a, 5 and 4a located within the wheel sector S, which can be worn down by the rail 3 and/or slide thereagainst and/or generate noise during sliding thereagainst. Those parts 2a, 5 and 4a of the railway wheel 1 which are exposed to said influence and/or permit said influence, are surface refined or improved with high energy, perfera- bly laser radiation, whereby a maximum thickness B of the surface refined parts 6 is selected so that the Hertzian pressure which affects the railway wheel 1 when said wheel is loaded with the maximum permitted pressure thereon is substantially carried by the body 7 of the railway wheel 1 beneath the surface refined parts 6, whereby loosening of said surface refined parts 6 from said body 7 during loading of the railway wheel 1 with the maximum permitted pressure is prevented or obstructed. The maximum thickness of the surface treated parts 6 is preferably 5 mm, whereby it is ensured that the Hertzian pressure affecting the railway wheel 1 when said wheel is loaded with the normally maxi¬ mum permitted pressure thereon, is substantially carried by the body 7 of the railway wheel 1 beneath the surface refined parts 6. To the melt obtained at the surface refine¬ ment, at least such a metal, metal alloy or metal mixture and/or at least such a ceramic is added, which permits that said parts 2a, 5 and 4a are less worn and/or get better sliding properties and/or give rise to less noise than what the base material of the body 7 of the railway wheel permits. With the expression surface refinement or improvement it is here meant surface coating and/or surface impregna- tion and/or surface recovery. This high-energy surface refinement can e.g. be accomp¬ lished by applying the beam 8 from a laser device (not shown) on said parts 2a, 5 and 4a while simultaneously adding said metallic materials 9 and/or ceramics 10 to the melt ob¬ tained by means of the beam 8. Preferably, said metal mate¬ rials 9 as well as ceramics 10 are added to the melt. Examples of metal materials 9 that can be added to the ment are yttrium, niobium, tantalum, nickel, chromium, cobolt, molybdenum, tin, lead, indium, zirconium, silicon, aluminium, titanium, tungsten or vanadium or at least one metal alloy or metal mixture containing at least one of these metals. Ceramics 10 which can be added to the melt belong e.g. to the group including carbides, nitrides, oxids or borides. At least one such metal 9, metal alloy or metal mixture and/or at least one such ceramic 10 can be added to the melt and/or the surface refinement of the wheel tread 2 and the transition portion 5 between the wheel tread 2 and rail flange 4 and eventually the rail flange 4 can be conducted in such manner that the wheel tread 2 and the transition portion 5 between said wheel tread 2 and the rail flange 4 and eventually said rail flange 4 are worn at substantially the same rate. The surface refinement can be carried out locally on the railway wheel 1 in such manner that substantial heating of the railway wheel 1 caused by the surface refinement only occurs locally within a small area in relation to the total range of the railway wheel 1 in and around the spot of sur¬ face refinement, whereby undesired extensive heating and thereby undesired changes of essential portions of the base material of the body 7 of the railway wheel 1 are avoided. The railway wheel 1 can be surface refined while it is mounted on a wheel axis, whereby said railway wheel 1 during the surface refinement is cooled preferably with cooling air so that heat generated during said surface re¬ finement is prevented from propagating into bearing parts in the railway wheel 1 and thereby preventing or obstruc¬ ting unfavourable heating of lubricant present in said bearing parts. Furthermore, the surface refinement is preferably ex¬ tended in such a way that it covers at least parts of the transition portion 5 between the wheel tread 2 and the rail flange 4 and also extends in over at least parts 2a of the wheel tread 2 and/or parts 4a of the rail flange 4. Hereby, the surface refinement can be extended in such a way that it covers the entire transition portion 5 between the wheel tread 2 and the rail flange 4 and at least the parts 2a, 4a of said wheel tread 2 as well as said rail flange 4 lo- cated closest to said transition portion 5. Furthermore, the surface refinement can be extended in such a way that it covers that part 2a of the wheel tread 2, which lies closest to the transition portion 5 and which is situated at a distance A (see fig. 8) from a centre point M of the wheel tread 2, whereby the distance A is preferably 10 - 20 mm. The surface refinement can also be extended in such manner that it covers at least parts of the height H of the rail flange 4 between the wheel tread 2 and outer parts 4b of said rail flange 4. Preferably, the surface refinement can be extended such that it is thickest primarily in the central parts 5a of the transition portion 5 between the wheel tread 2 and the rail flange 4 and such that it from its thickest portion at primarily central parts 5a of the transition portion 5 has a successively decreasing thickness in direction towards the centre point M of the wheel tread 2 and the outer parts 4b of the rail flange 4. However, it is often advantageous to surface refine the wheel tread 2 along its entire width, the entire transition portion 5 and the rail flange 4 all the way up to the outer parts 4b thereof and to about central portions of said outer parts 4b where said outer parts start to turn down in a di¬ rection towards the outer end surface of the railway wheel 1. The surface refinement can e.g. be extended from the central parts 5a of the transition portion 5 (preferably from the centre of said central parts 5a) in a direction towards the outer parts 4b of the rail flange 4 and there¬ after or before in a direction towards the wheel tread 2. The surface refinement can be extended by locating surface refining strings 11 beside each other within an area C extending peripherally around the railway wheel 1 in the running direction thereof, so that said railway wheel 1 is in contact with the rail 3 through said surface refining strings 11. Said surface refining strings 11 are shown schemati¬ cally in the drawings as thin lines, but they are in fact substantially wider than these lines. As is apparent from figs. 9 and 10, all these surface refining strings 11 are located in parallel with a plane or level D extending perpendicular or substantially per¬ pendicular to the centre axis 12 of the railway wheel 1. Furthermore, each surface refining string 11 may extend around the railway wheel 1 as an endless surface refining ring which, seen from the side in radial direction towards the railway wheel 1, can be straight. As is apparent from fig. 9, the distances between all surface refining strings 11 may be the same. As is shown in fig. 10 however, the distances between the surface refi¬ ning strings 11 within the central parts 5a of the transi¬ tion portion 5 (i.e. where the radius of the arcuate tran¬ sition portion 5 is the smallest) can be small, while the distances between the surface refining strings 11 on the wheel tread 2 and/or rail flange 4 are larger and may in¬ crease successively in a direction from the central parts 5a of the transition portion 5. As is apparent from fig. 11 some of the surface refi¬ ning strings 11 can be located peripherally around the rail- way wheel 1 and in parallel with the plane D, i.e. perpen¬ dicular to the centre axis 12, while other surface refi¬ ning strings 11 can be located in parallel with plane E, i.e. at an angle of 30 - 60° relative to said centre axis 12. From fig. 12 it is also apparent that the surface refi- ning strings 11 running in parallel with the plane D can be located on the transition portion 5 and on the parts 2a and 4a of the wheel tread 2 and rail flange 4 respec- tively, while the surface refining strings 11 running in parallel with plane or level E can be located on the rail flange 4 close to the part 4a. As is apparent from figs. 12 - 14, the surface refi- ning strings 11 can - instead of being straight - be wave formed, e.g. have sine-wave shape. Each wave formed sur¬ face refining string 11 can be designed as a peripherally around the railway wheel 1 extending surface refining ring and each such surface refining string 11 can extend sub- stantially in parallel with the plane D (see fig. 12). The wave formed surface refining strings can be located at the same or at various relative distances in the same way as the surface refining strings 11 described above in connec¬ tion with figs. 9 and 10. The wave shaped, surface refining strings 11 - and besides also the straight surface refining strings 11 - can be positioned as "broken", peripherally around the railway wheel 1 extending surface refining ring, as is shown in fig. 13. Alternatively, the wave formed surface refining strings 11 can be located such that they extend substantially in parallel with plane E (see fig. 14) . As is apparent from figs. 6 and 7, the surface refi¬ ning strings 11 can be located so relative to each other that they extend partly integrated with each other. Hereby, the surface refining strings can be integra- ted with each other so that a portion Fl of 2-50 %, pre¬ ferably 20-40 %, of the width F of a surface refining string 11 is integrated with a portion Fl of 2-50 %, preferably 20-40 %, of another surface refining string 11, whereby a certain portion Fl of the width F of a surface refining string 11 preferably is integrated with as large or sub¬ stantially as large a portion Fl of the width F of another surface refining string 11. This is illustrated in fig. 6 and 7, wherein however, the surface of the surface refi¬ ning strings 11 not yet has been smoothed or levelled for obtaining final surface smoothness. As is apparent from fig. 3, at least a certain part of the railway wheel can be surface refined by applying on its original surface 13 a material 9 and/or 10 which has been added to the melt such that at least portions 9a and/or 10a of this material will be located above the original surface 13. As is apparent from fig. 5, at least another certain part of the railway wheel 1 can be surface refined by im¬ pregnating its original surface 13 with the material 9 and/or 10 added to the melt, so that this material comp¬ letely or that at least the main portion thereof will be located beneath the original surface 13. The abovementioned application of material 9 and/or 10 on the original surface 13 may e.g. occur on the transi¬ tion portion 5 and the wheel tread 2, while the abovemen¬ tioned impregnation with material 9 and/or 10 of the origi- nal surface 13 may e.g. be carried out on the rail flange 4. During the surface refinement, at least a metal 9, a metal alloy or metal mixture and/or at least a ceramic 10 can be added to the melt, so that the added material 9 and/or 10 remains substantially unchanged in the melt. Finally, it should be mentioned that the railway wheel 1 can be preheated before the surface refinement, namely to a temperature above 200°C and that the surface refined parts of the railway wheel 1 preferably are ground for obtaining the required surface smoothness and surface fineness. The railway wheel 1 can be surface refined in its ori¬ ginal design, perferably when it is newly manufactured. Alternatively, a ring (not shown) which is provided, e.g. shrunk-on a railway wheel 1 and adapted to cover worn parts of the railway wheel 1, is surface refined in accordance with said method. The device and method according to the invention is not limited to what is defined above, but may vary within the scope of the following claims. An alternative example is that the maximum thickness B of the surface refined parts 6 in accordance with the requirements set can be 0,5 mm and any other thickness up to 5 mm, eventually increased with 10 % at the most.

Claims: Claims : 1. Device for improving the adhesitivity of surface refined parts (6) to the body (7) of railway wheels (1) , which surface refined parts (6) have been produced by trea¬ ting the railway wheel (1) with high energy generated pre- ferably by laser radiation (8), c h a r a c t e r i z e d i n that a maximum thickness (B) of the surface refined parts (6) is selected so that the Hertzian pressure which affects the railway wheel (1) when said wheel is loaded with the maximum permitted pressure thereon is substan- tially carried by the body (7) of the railway wheel (1) beneath the surface refined parts (6) , whereby loosening of said surface refined parts (6) from said body (7) du¬ ring loading of the railway wheel (1) with the maximum permitted pressure is prevented or obstructed. 2 . Device according to claim 1, c h a r a c t e r i ¬ z e d i n that the maximum thickness (B) of the surface refined parts (6) is 5 mm, whereby it is ensured that the Hertzian pressure affecting the railway wheel (1) when said wheel is loaded with the normally maximum permitted pressure thereon, is substantially carried by the body (7) of the railway wheel (1) beneath the surface refined parts (6) . 3. Method for obtaining a device for improving the adhesitivity of surface refined parts (6) to the body (7) of railway wheels (1) , which surface refined parts (6) are produced by treating the railway wheel (1) with high energy generated preferably by laser radiation (8), c h a r a c t e r i z e d b y selecting maximum thick¬ ness of the surface refined parts (6) so that the Hertzian pressure affecting the railway wheel (1) when said wheel is loaded with the maximum permitted pressure thereon is substantially carried by the body (7) of the railway wheel (1) beneath the surface refined parts (6) , whereby loosening of said surface refined parts (6) from said body (7) du¬ ring loading of the railway wheel (1) with the maximum permitted pressure is prevented or obstructed. 4. Method according to claim 3, c h a r a c t e r i ¬ z e d b y surface refining those parts (2a, 5, 4a) of the wheel tread (2) and/or the rail flange (4) and/or a transition portion (5) between said wheel tread (2) and said rail flange (4) which may be worn out by the rail (3) and/or slide thereagainst and/or generate noise during sli¬ ding thereagainst, by at least partly melting the surface layer thereof with the high energy which is generated pre¬ ferably by laser radiation (8) while at the same time adding to the melt produced thereby at least such a metal (9) , metall alloy or metal mixture and/or at least such a cera¬ mic (10) which permits that said parts (2a, 5, 4a) are less worn and/or get better sliding properties and/or give rise to less noise than what the base material of the body (7) of the railway wheel (1) permits. 5. Method according to claim 4, c h a r a c t e r i ¬ z e d b y adding to the melt at least such a metal (9), metal alloy or metal mixture and/or at least such a cera¬ mic (10) and/or conducting the surface refinement of the wheel tread (2) and the transition portion (5) between said wheel tread (2) and the rail flange (4) and eventually said rail flange (4) in such manner that the wheel tread (2) and the transition portion (5) between said wheel tread (2) and the rail flange (4) and eventually said rail flange (4) are worn at substantially the same rate. 6. Method according to any of claims 3 - 5, c h a ¬ r a c t e r i z e d b y conducting the surface refine¬ ment locally on the railway wheel (1) in such manner that substantial heating of the railway wheel (1) caused by the surface refinement only occurs locally within a small area in relation to the total range of the railway wheel (1) in and around the spot of surface refinement, whereby undesired extensive heating and thereby undesired changes of essential portions of the base material of the body (7) of the railway wheel (1) are avoided. 7. Method according to any of claims 3 - 6, c h a ¬ r a c t e r i z e d b y surface refining the railway wheel (1) while it is mounted on a wheel axis, whereby said railway wheel (1) during the surface refinement is cooled preferably with cooling air so that heat generated during said surface refinement is prevented from propagating into bearing parts in the railway wheel (1) and thereby preven¬ ting or obstructing unfavourable heating of lubricant pre¬ sent in said bearing parts. 8. Method according to any of claims 3 - 7, c h a ¬ r a c t e r i z e d b y extending the surface refinement in such a way that it covers that part (2a) of the wheel tread (2) which lies closest to the transition portion (5) and which is situated at a distance (A) from a centre point (M) of the wheel tread (2) preferably 10 - 20 mm from said centre point (M) of the wheel tread (2), and by further extending the surface refinement in such manner that it covers at least parts of the height (H) of the rail flange (4) between the wheel tread (2) and outer parts (4b) of said rail flange (4) . 9. Method according to any of claims 3 - 8, c h a - r a c t e r i z e d b y extending the surface refinement such that it is thickest primarily in the central parts (5a) of the transition portion (5) between the wheel tread (2) and the rail flange (4) . 10. Method according to claim 8, c h a r a c t e - r i z e d b y extending the surface refinement such that it from its thickest portion at primarily central parts (5a) of the transition portion (5) has a successively decreasing thickness in direction towards a centre point (M) of the wheel tread (2) and outer parts (4b) of the rail flange (4) . 11. Method according to any of claims 3 - 10, c h a ¬ r a c t e r i z e d b y starting the surface refinement from central parts (5a) of the transition portion (5) be¬ tween the wheel tread (2) and the rail flange (4) . 12. Method according to any of claims 3 - 10, c h a - r a c t e r i z e d b y extending the surface refinement from the central parts (5a) of the transition portion (5) in a direction towards outer parts (4a) of the rail flange (4) and thereafter or before from said central parts (5a) of the transition portion (5) in a direction towards the wheel tread (2) . 13. Method according to any of claims 3 - 12, c h a - r a c t e r i z e d b y extending the surface refinement by locating surface refining strings (11) beside each other within an area (C) extending peripherally around the rail¬ way wheel (1) in the running direction thereof, so that said railway wheel (1) is in contact with the rail (3) through said surface refining strings (11) . 14. Method according to claim 13, c h a r a c t e ¬ r i z e d b y locating at least one of the surface re¬ fining strings (11) so that it runs in parallel with a plane or level (D or E) extending at an angle to a centre axis (12) of the railway wheel (1) . 15. Method according to claim 14, c h a r a c t e ¬ r i z e d b y locating at least one of the surface refi¬ ning strings (11) so that it runs in parallel with a plane or level (D) extending perpendicular or substantially per- pendicular to the centre axis (12) of the railway wheel (1) . 16. Method according to claim 14, c h a r a c t e ¬ r i z e d b y locating at least one of the surface refi¬ ning strings (11) such that it runs in parallel with a plane or level (E) extending at an angle ( ©< ) of 30-60° relative to the centre axis (12) . 17. Method according to any of claims 13-16, c h a ¬ r a c t e r i z e d b y designing at least one of the surface refining strings (11) as an at several locations broken, in peripheral direction around the railway wheel (1) extending surface treating ring. 18. Method according to any of claims 13-17, c h a ¬ r a c t e r i z e d b y designing at least one of the surface refining strings (11) such that it, seen from the side in radial direction towards the railway wheel (1) , is wave formed, preferably sine-wave formed. 19. Method according to any of claims 13-18, c h a ¬ r a c t e r i z e d b y locating peripherally around the railway wheel (1) extending surface refining strings (11) so that the distance between at least two surface refining strings (11) located within certain parts of the area, pre¬ ferably such central parts (5a) of a transition portion (5) between the wheel tread (2) and the rail flange (4) , is less than the distance between surface refining strings (11) located on other parts of the railway wheel (1) , preferably parts (2a and/or 4a) of the wheel tread (2) and/or the rail flange (4) . 20. Method according to claim 19, c h a r a c t e ¬ r i z e d b y locating the surface refining strings (11) within said central parts (5a) such that the distances be¬ tween said strings are the same or substantially the same, while surface refining strings (11) on parts (2a and/or 4a) of the wheel tread (2) and/or the rail flange (4) are loca¬ ted so that the distances between these strings increase successively in a direction from the central parts (5a) . 21. Method according to claim 19 or 20, c h a r a c ¬ t e r i z e d b y locating surface refining strings (11) within an arcuately profiled transition portion (5) between the wheel tread (2) and the rail flange (4) so that the distance is less between surface refining strings (11) located in central parts (5a) of the transition por¬ tion (5) where the radius thereof is less, than between surface refining strings (11) located in outer parts (5b, 5c) of said transition portion (5) where its radius is larger. 22. Method according to any of claims 13-21, c h a ¬ r a c t e r i z e d b y locating peripherally around the railway wheel (1) extending surface refining strings (11) within certain parts of said railway wheel (1) , pre¬ ferably the parts thereof in which the wheel tread (2) and the transition portion (5) between said wheel tread (2) and the rail flange (4) are included, and locating other surface refining strings (11) running in parallel with levels or planes which extend at an angle ( o< ) of 30-60° relative to the centre axis (12) of the railway wheel (1) , within other parts of said railway wheel (1) , preferably those parts in which the rail flange (4) is included. 23. Method according to claim 22, c h a r a c t e ¬ r i z e d b y locating the surface refining strings (11) which run in parallel with a level or plane (D) extending perpendicular to the centre axis (12) , on the transition portion (5) and on the parts (2a, 4a) of the wheel tread (2) and the rail flange (4) lying closest to said transi¬ tion portion, while the surface refining strings running in parallel with a level or plane (E) which extends at an angle of 30-60° to the centre axis (12), are located on the rail flange (4) adjacent to the part (4a) thereof situated close to the transition portion (5) . 24. Method according to any of claims 13-23, c h a - r a c t e r i z e d b y locating one or more surface refining strings (11) on top of outer parts (4b) of the rail flange (4) . 25. Method according to any of claims 3 - 24, c h a ¬ r a c t e r i z e d b y surface refining at least a certain part of the railway wheel (1), e.g. a part of the wheel tread (2) of said railway wheel (1) and/or a transi¬ tion portion (5) between a wheel tread (2) and a rail flange (4) of said railway wheel (1), by applying on its original surface (13) a material (9 and/or 10) which has been added to the melt such that at least portions (9a and/or 10a) of this material will be located above the original surface (13) . 26. Method according to any of claims 3 - 25, c h a ¬ r a c t e r i z e d b y surface refining at least a certain part of the railway wheel (1) , e.g. a part of a rail flange (4) of the railway wheel (1) , by impregnating its original surface (13) with the material (9 and/or 10) added to the melt, so that this material completely or at least the main portion thereof will be located beneath the original surface (13) of said part. 27. Method according to any of claims 3 - 26, c h a ¬ r a c t e r i z e d b y surface refining at least a certain part of the railway wheel (1) , e.g. a part of the wheel tread (2) of said railway wheel (1) and/or a transi¬ tion portion (5) between a wheel tread (2) and a rail flange (4) of said railway wheel (1) , by applying on its original surface (13) a material (9 and/or 10) which has been added to the melt such that at least portions (9a and/or 10a) of this material will be located above the original surface (13), and by also surface refining at least a certain other part of the railway wheel (1) , e.g. a part of a rail flange (4) of the railway wheel (1), by im¬ pregnating its original surface (13) with the material (9 and/or 10) added to the melt, so that this material comple¬ tely or at least the main portion thereof will be located beneath the original surface (13) of said part. 28. Method according to any of claims 3 - 27, c h a ¬ r a c t e r i z e d b y adding to the melt during the surface treatment, at least a metal (9) , a metal alloy or metal mixture and/or at least a ceramic (10) , so that the added material (9 and/or 10) remains substantially unchan- ged in the melt. 29. Method according to any of claims 3 - 28, c h a ¬ r a c t e r i z e d b y preheating the railway wheel (1) in its entirety before the surface refinement, whereby said railway wheel preferably is preheated to more than 200°C. 30. Method according to any of claims 3 - 29, c h a ¬ r a c t e r i z e d b y grinding the surface refined parts of the railway wheel (1) for obtaining the required surface smoothness and/or surface fineness. 31. Method according to any of claims 3 - 30, c h a ¬ r a c t e r i z e d b y surface refining the railway wheel (1) in its original design. 32. Method according to any of claims 3 - 31, c h a ¬ r a c t e r i z e d b y surface treating a ring which is provided, e.g. shrunk-on a railway wheel (1) and covers worn parts thereof.

Inventors: LENNART OLOFSSON JOHAN, LENNART, OLOFSSON, JOHAN
Applicants: OLOFSSON JOHAN LENNART, LENNART, OLOFSSON, JOHAN
Application year: 1994
Main classification: B60B17
IPC codes: B60B17, C21D1, C21D9, C23C26